The Study

01/02/2025

Ive tried to summarise the impact of transition periods ending for NCC 2019 in WA from May -

May 2025 will see the end of transition periods for NCC2019, and projects submitted for permits will need to meet the increased requirements of NCC 2022.

16/12/2024

Interesting modelling done on the financials for higher performance. Interesting that people will often be happy to spend $25k for a guest bedroom (for resale) but higher specs for energy performance is considered a hard sell. Higher performance means lower costs, a spare room does not save money. When we will value higher performance housing over another store room?

New modelling shows that spending $25,000 on improving energy efficiency – and driving an EV – can save $300,000 over a 25-year mortgage.

21/07/2023

Over the last few weeks we have looked at the impact of NCC22 on energy compliance due to the updated weather files, adjusted star bands and different rules for how assessors must model.

We looked at ten houses across nine climate zones and two NCC versions - a total of 180 simulations!

The big winner appears to be Climate zone 54 - Mandurah, with all ten houses getting a boost in performance under NCC22. Zone 49 - Katanning appears to be the hardest hit by the changes, with not only a jump from six to seven stars, but the adjusted ratings mean an extra 0.30 stars or so will need to be found!

Of the 180 simulations - the largest jump was +0.8 stars in Zone 33 - Broome, and the largest drop was -0.7 stars in Zone 49 - Katanning. 80% of results were within 0.4 stars between versions. The average across all zones and all dwellings was +0.09 stars from NCC19 to NCC22

There were not any really clear patterns for the dwellings themselves - some dwellings enjoyed a boost in one zone along with other dwellings, but in another zone has taken a drop where other dwellings have gone up. It might be that dwellings with higher heating and/or cooling loads perform differently in the zones.

Please note the maps I have included are indicative only - climate zones work on postcodes. You can search the appropriate zone by using the NatHERS climate zone map
https://www.nathers.gov.au/themes/custom/govcms8_uikit_starter/climate-map/index.html

We hope this little study into the changes between NatHERS versions has been interesting - would you like to see further info like this?

Disclaimer: The Climate Zone Map is provided for general reference only and was last updated in March 2013. It should not be relied on for accurate climate zone information. You should exercise your own skill and care when using the Climate Zone Map and carefully evaluate the accuracy, currency, com...

18/07/2023

The last climate zone we have looked at in this project is Zone 49 - Katanning. This zone covers the inland areas of the SW of WA - and includes the townships of Kojonup, Cranbrook, Wagin and Boyup Brook .

Only 160 dwellings have been certified in the last three years, and all between 6.0 and 7.4 stars - according to the Aust. housing data portal.

Our ten test houses rated at 6.37 stars on average in this climate zone under NCC19. Updated for NCC22 - the average rating dropped to 6.05 stars, a reduction of -0.32 stars.

While two dwellings did enjoy a small improvement of +0.2 stars, generally the designs had a reduction in performance, up to -0.7 stars for two designs.

What does this mean?
The updated weather files and star bands for Zone 49 are not likely to be favourable in this climate zone, and could be considered that stringency is being increased significantly in this zone. Ideally - a rating of at least 7.3 stars should be targeted under NCC19 to retain compliance under NCC22.

14/07/2023

Climate zone 54 is next up - Mandurah. This climate zone includes the coastal strip south of Perth right down to Augusta, and includes the towns and areas surrounding Bunbury, Busselton and Margaret River. We do a lot of work in this climate zone, and feel like we have a pretty good handle on how to achieve good results in this climate zone!

Australian Housing data reports 5,272 dwellings have been certified in this climate zone, with a wide spread of ratings - but most between 6.0 and 6.5 stars, with a decent level of higher performing designs (around 25% rating at 6.5-7.5 stars)

Our ten recent houses rated at 6.89 stars on average in this climate zone. With no changes to the design or specs, only updated for NCC22 requirements and information - the average rating rose to 7.28 stars - an increase of 0.39 stars.

This climate zone was the most favourable of the nine we have looked at - with all designs getting some performance boost of between +0.2 stars and +0.6 stars

What does this mean?
The updated weather files and star bands are likely to be quite favourable in this climate zone. Its likely that a design which achieves 6.6 stars under NCC19 is likely to achieve compliance under NCC22 with no changes to design or specification.

11/07/2023

Next up in our review of the impact of NCC22 - lets have a look at Zone 13 - Perth Airport. This climate zone covers a large part of Perth metro, between the coastal strip and hills areas.

Housing data shows 12,162 dwellings certified in this zone over the last three years, with a wide spread between 3.0 stars and 9.0 stars - with close to two-thirds rating between 6.0 and 6.5 stars.

Our ten test houses rated, on average, 6.97 stars in this climate zone under NCC19. Updating the modelling for NCC22 - the average rating rose to 7.19 stars - an increase of +0.22 stars,

Two designs had a negative result of -0.1 stars, but two designs improved by +0.6 stars, with the rest generally enjoying a small improvement.

What does this mean?
The updated energy requirements under NCC22 are likely to be slightly favourable in this climate zone. Targeting a rating of approx 6.8 stars under NCC19 is likely to mean the minimum seven star requirement will be met under NCC22.

07/07/2023

Manjimup - Zone 57 - in an interesting climate zone, did you know it is not even used for the town of Manjimup? Instead, it is used for Nannup and a the areas to the West of Manjimup, as well as an isolated area around Rocky Gully for some strange reason.

The Aust. housting data portal reports only 143 dwellings certified in this climate zone in the last three years - all rating between 6.0 and 6.9 stars,

We have taken ten recently modelled projects, and located them in Zone 57. On average, these ten dwellings rated at 5.77 stars. We then adjusted the requirements to reflect the weather files, star rating bands, and updated assessment conditions for NCC22 - and the average star rating dropped slightly to 5.75 stars, a drop of 0.02 stars.

Most dwellings in this zone had no change to their star rating, some lost -0.1 stars, while others gained +0.1 stars.

What does this mean?
The impact of NCC22 updates is unlikely to have much of an impact in this climate zone. Projects rating at 7.0 stars under NCC19 will likely be compliant at 7.0 stars under NCC22.

04/07/2023

Swanbourne - Zone 52 is the next climate zone to have a look at the impact of NCC22 changes. This climate zone is used for the narrow coastal strip in Perth metro, and extends north to Lancelin.

2,856 dwellings have been certified in this zone in the last three years, according to thehousing data portal. A very wide spread from 3.0 stars to 9.0 stars - but again we see the majority (60%) are at 6.0 - 6.5 stars

Our ten test houses rated on average 6.83 stars under NCC19. When run with the same design and specifications for NCC22 - they rated on average 7.02 stars - an average increase of 0.19 stars. While two designs did drop in rating (by -0.2 stars) - most houses improved by +0.1 stars, with one design jumping +0.6 stars

What does this mean?
NCC22 is likely to be slightly favourable in this climate zone. A rating of 6.8 stars under NCC2019 is likely to achieve 7.0 stars under NCC22

30/06/2023

Keeping the focus on how changes to NCC22 will impact energy compliance. The next climate zone to look at is Zone 47 - Bickley. This zone covers the hills area behind Perth metro, but does also extend to the coast just south of Mandurah, and includes Harvey and surrounds.

In the last three years - 448 houses have been certified here, with a wide spread between 4.5-7.5 stars, with two-thirds rating at 6.0-6.5 stars - according to the Australian housing data portal.

Taking ten recent houses we have modelling - in this zone they rate on average at 6.38 stars. Updating these for NCC22 requirements, the average rises to 6.50 stars - an average increase of +0.12 stars

What does this mean?
Projects in climate zone 47 are largely unimpacted by the change from NCC19 to NCC22 - the requirements under both regulations are pretty similar, and results can be expected to be pretty close under either method - a seven star rating under NCC19 is likely to be needed to achieve a seven star rating under NCC22.

27/06/2023

Next up in our look at the impact of NCC22 on energy in WA - we turn our attention to NatHERS climate zone 33- Broome Airport

This climate zone is centred around Broome in the kimberley region - the housing data portal reports 211 dwellings certified here in the last three years, with a range of 5.5-7.5 stars

Our ten recent houses rated on average 5.64 stars in this zone under current requirements. Under NCC22 - the average rating rose to 5.8 stars (no changes to design or specifications). So an average increase of +0.16 stars

Of our ten houses, only one saw a reduction in star ratings, most designs saw no change to the rating, and two designs saw large improvements of +0.7 stars.

What does this mean?
It's likely that designs will need to achieve seven stars under NCC19 to achieve seven stars under NCC22 - but you may get lucky and see a decent boost in performance only need to achieve around 6.3 stars under current requirements.

23/06/2023

Continuing with our look at the impact of seven stars / NCC22 - the next climate zone we will look at is 58 - Albany Airport. This climate zone covers the coastal strip around Albany, and extends inland over Manjimup and Bridgetown.

This is a climate zone I personally find quite stringent - the focus really needs to be on maximising winter solar passive gain, I find it hard to have too much shading in this climate - there is very little cooling energy needed in the simulations.

The housing data portal reports 724 dwellings in the last three years, with a wide spread of 5.0-7.5 stars, however the majority at 6.0-6.5 stars.

Our ten test houses rated on average in Albany at 5.76 stars. Updated for NCC2022 - these ten houses had an average rating of 5.61 - a small drop of 0.15 stars on average. While three of the ten houses had a small increase of +0.1 stars, most had a reduced rating of -0.2 stars, with one house dropping by -0.6 stars.

What does this mean?
Projects in climate zone 58 may need to target 7.1-7.2 stars under current requirements to achieve seven stars under NCC22. This may be problematic as I often find dwellings in this zone struggle to achieve compliance already under six star requirements! Please try to send designs to early assessment to get feedback on how things are looking as early as practical!

20/06/2023

NCC2022 is still a long way from becoming mandatory in WA - but we have started to look at the impact of shifting to seven star minimums, and the introduction (in WA) of heating and cooling load limits.
Many are aware that when transition periods end, dwellings will need to achieve seven stars in NatHERS software, up from the current six star rating - but did you know that the "stars" under NCC19 and NCC22 will be different? There are different weather files, adjusted star bands and different rules for how assessors must model.

We have had a look at the impact of these changes. First up - focusing on the Esperance Climate zone, which covers the coastal nullabor strip in SE WA.

According to the Australian housing data portal - In the last three years, 56 dwellings have been certified here, all rating between 6.0 and 6.9 stars.

We have taken ten recent modelling projects, and put them in the Esperance Climate zone - the average rating came to 6.06 stars
We then changed the modelling to reflect NCC22 weather files, star bands and modelling rules (but no changes to designs or specifications) - and the average rating came to 6.29 stars

Of the ten houses tested, only one had the star rating reduce between NCC19 and NCC22 (and only at -0.1 stars). Typically - the houses all rated better under NCC22. Most saw an increase of +0.1 star, and one house went up by 0.6 stars

What does this mean - I would summarise these findings to suggest that under NCC22, in this climate zone - its likely a dwelling only needs to achieve around 𝟔.𝟖 𝐬𝐭𝐚𝐫𝐬 under current energy modelling methods. If your design is achieving around this level currently, it is likely that no further upgrades will be needed to achieve seven stars under NCC22